Why Does Antihistamines Cause Weight Gain?

It is very possible that the intake of antihistamines may cause weight gain.

Antihistamines can be defined as commonly used over-the-counter medications that treat the symptoms of allergic conjunctivitis and allergic rhinitis. These medications block histamines, chemicals that are produced by our immune system when it recognizes certain elements as a threat for us. Antihistamines are particularly useful for treating common allergy symptoms such as runny nose, sneezing, eye itching and nose itching.

Some older antihistamines, such as Benadryl, cause some well-known side effects such as dry mouth, drowsiness, and urination problems. On the other side, newer antihistamines, such as Allegra, cause fewer side effects.

Research on Antihistamines and Weight Gain

Obesity journal has published a study in 2010 that featured an association between the usage of antihistamines and obesity. This study found out that 900 studied people who were taking antihistamines were at a higher risk of becoming obese. The reason for that remains unclear, but there are certain theories about why do antihistamines promote obesity.

Some scientists theorize that antihistamines promote obesity since their structure is similar to the structure of psychiatric drugs that are associated with weight gain. Another theory why antihistamines cause weight gain is that they increase appetite.

Some older antihistamines, like Periactin (cyproheptadine), were actually given to people for the purpose of increasing their appetite and weight gain. Moreover, the target group to which Periactin was given was cancer patients and underweight children.

Why Does Antihistamines Cause Weight Gain?

Doctors believe that antihistamines promote weight gain because they cause decreased levels of energy in persons that take them. Decreased levels of energy caused by antihistamines intake in turn cause the lack of desire for performing physical activity that prevents physical activities such as running, jogging, cycling, swimming, playing various types of sports, and other forms of physical activity.